I voted no.
Oddly enough I have a friend who was in this exact situation and went to jail for it. She was at a hotel when she found a little girl wandering out by the pool she asked the girl where her mom was and she told her she was not there, but she was there with her grandma. So my friend takes the little girl by the hand and starts walking to the lobby area to talk to security when the little girls grandma starts screaming "SHE IS TAKING MY GRANDDAUGHTER STOP HER!!" The security guards call 911 and detain my friend, police came and took her to jail for 6 days, she had to go to court and she got probation.
Unfortunately, this is a cautionary tale because I think sometimes people do want to help but are afraid they might be misunderstanding the situation and don't want to get in trouble or make someone upset.